Memory Issue with MySqli code

[Deepzone]

I have the following code the lookup data from a database.  It runs okay on my llocal machine but it give me "Fatal error: Allowed memory size of 33554432 bytes exhausted" whenit runs on hosting server.  It indicates fatal error at line of $r[field3]); 

 

I googled the error and found the response for similar situation is to re-code to prevent memory leak.  Can anyone point out how the following can be improve to prevent the error from happening.  Thanks a lot.

 

 

 

 

$stmt = $database_connection->stmt_init();
    if ($stmt->prepare("SELECT keyA, field1, field2, field3 FROM tableA JOIN tableB ON tableA.field1 = tableB.keyB JOIN tableC ON tableA.field2 = tableC.keyC
        WHERE field3 LIKE ?")) {
        
        $stmt->bind_param('s', $likeString);
        $stmt->bind_result($r['keyA'],
            $r['field1'],
            $r['field2'],
            $r['field3']);
        if (!$stmt->execute()) {
             echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
            exit();
        }    
        while($stmt->fetch()){    
            foreach( $r as $key=>$value ) {
                $row_tmb[ $key ] = $value;
            }
            $r[] = $row_tmb;
        }

    return $r;

[jazzman1]

Maybe, you have open more than one mysqli statements connection to the server, I don't know